In a press release after the close, Millennium said MLN02 showed statistically significant improvement in the clinical remission rates of patients treated with the drug, compared with those who received a placebo. The company also said the drug appeared to be well-tolerated in the trial, as was the case in another study that examined the drug as a treatment for Crohn's disease.

The results from both studies were presented at Digestive Disease Week, a gathering of physicians and researchers in gastroenterology, in Orlando, Fla. The results from the separate Phase II study of MLN02 in patients with mild to moderate Crohn's disease were initially announced last fall. The Crohn's disease study didn't meet its primary objective.

Millennium is developing MLN02 in collaboration with Genentech ( DNA), which holds the exclusive worldwide commercialization rights. In Instinet trading after the closing bell, shares of Millennium were gaining 82 cents, or 6.1%, to $14.37.